As a method of making color correction for improving a color reproduction effect in a color reproduction process of a printer or printing press, a method of converting data on an input color space into data on an output color space by a color masking method of obtaining data on an output color space by making matrix operations of data on an input color space is prevalently used.
However, the output characteristics of a color printer or printing press exhibit strong nonlinearity. Therefore, in a global method such as the color masking method, i.e., a color correction method in which a change in element of a matrix influences the overall output color space, the characteristics of a color printer or printing press cannot be satisfactorily approximated in the entire color gamut.